Allen replaces Hue Jackson, who was fired after going 8-8 in his lone season on the job. The Raiders lost four of their last five games.

Allen becomes the first Raiders' head coach with a defensive background since Hall of Famer John Madden was hired in 1969.

In Allen's first season as an NFL coordinator, the Broncos defense went from last in both total yards and points allowed in 2010 to 20th and 24th in those categories.

The 39-year-old Allen spent 10 seasons as an assistant coach in the NFL, four with the Atlanta Falcons and five with the New Orleans Saints, before being hired by Broncos coach John Fox to be his defensive coordinator.